Briefly, the test consisted of a negative control (nil well, i.e., whole blood without antigens or mitogen) , a positive control (mitogen well, i.e., whole blood stimulated with the mitogen phytohemagglutinin [PHA]) and two sample wells, i.e., whole blood stimulated with either of the M. tuberculosis-specific antigens, Early Secretory Antigen Target 6 (ESAT-6) or Culture Filtrate Protein 10 (CFP-10).